Barbazul: you asked a very complex question but first you need to see how they measure the light that you're using for what you want to do. I don't know if I have all the answers but I'll try to help you. First, wattage is the load or amount of current or electricity that the lamp uses. As I recall from a Physics class I took in the mid 70's, but don't hold me to it because I don't have the book in front of me, it's amps draw times times voltage, and it's usually read in a relatively small number like; example: 14, 17, 29, 40, 60, 100 watts or more, etc. What that really means is that the more watts you use the more expensive it is to operate. That's what got us all into those little curly-cue CFL's and dropped my electric bill so low that on a level pay I don't even get out of tier one with the electric company part of the year. The really tricky part of this is that they advertise wattage of electricity that they use compared to the equivalent used by an incandescent lamp. The ones I just bought claim they only draw 14 watts but they put out the same light as a sixty watts incandescent bulb. The one I use on my clone mother draws 29 watts and is equivalent to a 100 watt incandescent. Now is that clear to you, or are you just as confused as the rest of us? But we're not done yet.
Lumens is the amount light, the intensity it projects, the brightness; and that's usually measured in hundreds. I don't know where the top of the scale is but the new brighter, Ecosmart CFL lamps I just changed over to advertise that they generate 850 lumens and now you don't have to damned light a match to find them at night when they're turned on like their earlier predecessors that my wife used to bitch about. Now let's consider the color of the light they're producing.
Color, frequency or temperature of the light it produces when it's run through a prism and seen in the available spectrum of colors is measured in Kelvins, K's. These new lamps I bought are rated at 4,800K's, which is pretty close to the T-5 I have in my grow tent. The lower the K's, the warmer the light and the higher the K's the cooler the light. Cool is for grow and red is for flowering. If you can keep that straight think about what the sun produces during the year. In the spring and early summer the light is cool, it has a higher K number and it's greener. Grow lamps are green and that's the light suitable for vegging. Come fall we get those beautiful warm red orange sunsets and red is a flowering light.
Now lets look at the practical side of this. From seed sprouting and through vegging I feed my babies a high N and low P and K diet to go along with the grow lights schedule. Right now I'm using 5,000K grow lamps for my plants to veg in. I'm told, this is a moderately green light they like for growth and photosynthesis. A friend of mine uses 6,000K's lamps and another friend uses 6,500K's. I was warned against it by a person I trust at the hydro store. The other ones cost a little more but he claimed to see less light related problems with the 5,000K's so that's what I bought and they've worked fine. We usually have these on anywhere from 24, 20 or 16 hours a day. You choose.
When my plants begin to preflower I change their diet to a lower N and higher P-K nutrient blend and the lamps in the fixture to red flowering lights that are rated at only 2,700K. I also drop the light interval; the time that they're on. Some folks go directly to a 12/12 schedule but I use a progressive light schedule that starts at 20 hours of light at seed planting with 4 hours of resting darkness and reduces the light by one hour a week, but that's another issue I explained here already in another post. After some experimentation I settled on a bottom figure of 10 hours of light and 14 hours of darkness until the last week of harvest and the strains I'm growing seemed to really like it.
So if you're asking questions like this I suggest the following:
1. Read: SeeMoreBuds book,
marijuana BUDS FOR LESS GROW 8 OZ. OF BUDS FOR LESS THAN $100.
2. Read: Jorge Cervantess book,
marijuana HORTICULTURE THE INDOOR/OUTDOOR MEDICAL GROWERS BIBLE.
3. Read: Ed Rosenthals,
marijuana GROWERS HANDBOOK.
4. Youll want to read: Mc Carthys book,
GROWING marijuana.
5. Youll also want to subscribe to,
HIGH TIMES, magazine. Each issue is chocked full of useful information. . All these resources are very well written, well illustrated and packed with information that will answer most of your questions before you know to ask them. This will save you and your plants a lot of anxiety. There's another excellent book I'm reading right now but it's in the bathroom and I'd have to go through the bedroom where my honey is sleeping. Go to your local Barns and Noble bookstore they have a great selection. I hope this helped. HSA